Among all protocols, TF QKD [1]} promises high key rates over long distances to beat the repeater-less bound, which enhances the key rate to a square-root scaling (\(\sqrt{\eta }\) ) to the channel transmittance. Significantly, the experimental demonstrations of TF-QKD [2]}, [3]}, [4]}, [5]}, [6]}, [7]} achieved a record-long distribution distance of more than 500 km [6]}, [7]}. However, all these experiments were implemented in a laboratory, leaving the question that whether this fancy protocol is feasible in a practical scenario.
